Doctors Without Borders called for an independent investigation Thursday into the airstrike on a hospital that killed at least 25 people this week in northern Syria.

The international aid organization - known by its French initials MSF - said in a statement that the airstrike "was probably carried out by the Syrian-government-led coalition that is predominantly active in the region."

"Attacks on health facilities and other civilian targets must stop, and be subject to independent investigations," said MSF International President Dr. Joanne Liu.

Among those killed in the February 15 airstrike in Maraat al-Numan, Idlib province were nine medical personnel and 16 patients. Ten people were wounded in the attack.

A Pentagon spokesman told reporters Tuesday that aircraft from the U.S.-led coalition in Syria were not involved and that the U.S. could not say with any specificity "who was directly responsible."